Date: Wed, 14 Mar 2001 03:13:23 -0800 From: Mike Smith <msmith@freebsd.org> To: Pete French <pfrench@firstcallgroup.co.uk> Cc: stable@FreeBSD.ORG Subject: Re: Disk I/O problem in 4.3-BETA Message-ID: <200103141113.f2EBDNn04877@mass.dis.org> In-Reply-To: Your message of "Wed, 14 Mar 2001 11:06:13 GMT." <E14d96b-000CkE-00@dilbert.fcg.co.uk>
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> > What doesn't appear to have been mentioned is how exactly do we turn off
> > write caching on SCSI drives. From poking around the best I could work
> > out was to run 'camcontrol modepage da0 -m 0x08 -e -P 3' and set WCE to
> > 0 where 0x08 comes from /usr/share/misc/scsi_modes.
>
> ...and on a related note, how do you do it on SCSI drives that are
> hnaging off the back of a RAID controller, where camcontrol doesnt
> seem to be useable (unless I've got the wrong end of the stick completely)
Put battery-backed RAM on the RAID controller, and use the RAID
controller setup to disable write caching on the drives. Mylex, at
least, let you do this.
--
... every activity meets with opposition, everyone who acts has his
rivals and unfortunately opponents also. But not because people want
to be opponents, rather because the tasks and relationships force
people to take different points of view. [Dr. Fritz Todt]
V I C T O R Y N O T V E N G E A N C E
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